function [x_dJh_sfoot_mat] = dJh_sfoot_mat(x)
x_dJh_sfoot_mat=[0.,0.,0.0508.*(3..*cos(x(3)) + sin(x(3))).*x(12),0.,0.,0.,0.,0., ...
  0.;0.,0.,(-0.0508).*(cos(x(3)) + (-3.).*sin(x(3))).*x(12),0.,0., ...
  0.,0.,0.,0.;0.,0.,0.,0.,0.,0.,0.,0.,0.];
